The present invention generally relates to refrigerant charging apparatus and, in a preferred embodiment thereof, more particularly provides a specially designed refrigerant charging/pressure testing hose assembly useable to charge a refrigerant circuit.
A common technique for checking the refrigerant charge of a refrigerant circuit, for example in an automotive vehicle air conditioning system, and adding a relatively small quantity of refrigerant to the circuit if necessary, is to first check the pressure within the circuit by providing a hose with a pressure gauge operatively connected thereto, coupling an end of the hose to a service fitting portion of the circuit and then reading the pressure gauge. If the pressure gauge reading indicates that additional refrigerant needs to be added to the circuit, the pressure gauge hose is removed from the service fitting, and a separate charging hose assembly is used to add refrigerant to the circuit.
The charging hose assembly typically includes a coupling at one end which is releasably securable to the service fitting, and a shutoff valve at its opposite end that may be secured to the outlet of a pressurized refrigerant container. The coupling is secured to the service fitting, and the valve is opened to flow refrigerant into the circuit. After this is done, the charging hose assembly is removed from the service fitting, and the pressure gauge hose is again connected to the service fitting to provide a pressure reading indicative of the new refrigerant charge level in the circuit.
If the pressure reading is not sufficiently high, the pressure gauge hose assembly is removed and the charging hose assembly reattached to the service fitting to add still more refrigerant to the circuit. The circuit is then pressure tested again using the separate pressure gauge hose assembly. These two separate steps are repeated, using the separate hose assemblies, until the measured pressure within the circuit indicates that the circuit is adequately charged with refrigerant.
This conventionally required use of separate pressure reading and refrigerant charging hose assemblies to check and adjust the refrigerant charge in a refrigerant circuit such as an automotive air conditioning system tends to be both tedious and time consuming. A need thus exists for improved apparatus and methods for measuring the pressure of a refrigerant circuit and adding refrigerant thereto if necessary it is to this need that the present invention is directed.
In carrying out principles of the present invention, in accordance with a preferred embodiment thereof, a specially designed refrigerant charging/pressure testing assembly is provided for use in charging and pressure testing a refrigerant circuit, such as in an automotive air conditioning circuit, having a service inlet fitting.
The assembly, which representatively complies with SAE standard J2196, is interconnectable between the service fitting and an outlet portion of a pressurized refrigerant container and, in a preferred embodiment thereof, comprises (1) a conduit, representatively a length of flexible refrigerant charging hose, having first and second ends; (2) a coupling structure, representatively a quick disconnect fitting, secured to the first conduit end and being connectable to the service fitting; (3) a shutoff valve, representatively a piercing-type shutoff valve, secured to the second conduit end and being connectable to the refrigerant container outlet portion; (4) a pressure gauge connected in the conduit between the coupling structure and the shutoff valve and being communicated with the interior of the conduit; and (5) a check valve connected in the conduit between the pressure gauge and the shutoff valve, the check valve being operative to block fluid flow therethrough toward the shutoff valve.
To check the adequacy of the refrigerant charge in the circuit, the coupling structure is simply connected to the service fitting of the circuit and the pressure gauge is read. Illustratively, and not by way of limitation, the pressure gauge is a dial-type gauge having a face on which a normal pressure range is marked, such range being indicative of an adequate refrigerant charge in the circuit. Thus, when the gauge needle is within the marked normal range, the circuit does not need an additional refrigerant charge.
If the circuit does need additional refrigerant (and the shutoff valve has not been previously connected to the refrigerant container outlet) the shutoff valve is connected to the refrigerant container outlet and used, representatively by opening and closing it to inject separate amounts of refrigerant from the container into the circuit via the conduit, until the gauge pressure indicates that the circuit is adequately charged.
Using conventional apparatus and methods, this circuit pressure testing and refrigerant charging process previously required two items of equipmentxe2x80x94(1) a pressure gauge and associated hose, and (2) a separate charging hose which was used in conjunction with a refrigerant supply canister if additional refrigerant was needed in the circuit as indicated by the prior use of the separate pressure gauge/hose assembly. By using the specially designed refrigerant charging/pressure testing assembly of the present invention, this previous necessity of testing the circuit pressure with one structure and then removing the first structure and replacing it with a second structure used to add refrigerant, if needed, to the circuit is eliminated.
The refrigerant charging/pressure testing assembly thus advantageously provides for easier and quicker refrigerant checking and charging compared to conventional techniques and apparatus. The assembly permits the addition of refrigerant to the circuit in metered amounts, does not require the disconnection of the charging hose to measure pressure, and eliminates guesswork with respect to the amount of additional refrigerant needed by the circuit.